


Skinny Dipping

by AHeartAway



Category: Gravity Falls
Genre: F/M, Sibling Incest, Twincest, pinecest - Freeform
Language: English
Status: Completed
Published: 2017-08-02
Updated: 2017-08-02
Packaged: 2018-12-10 09:13:38
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,192
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11688573
Author URL: https://archiveofourown.org/users/AHeartAway/pseuds/AHeartAway
Summary: This is for my friend and pinecest roleplay partner, Sunny. Cause I would never have had the courage to admit to myself that I shipped these two if it wasn't for you.





	Skinny Dipping

**Author's Note:**

> This is for my friend and pinecest roleplay partner, Sunny. Cause I would never have had the courage to admit to myself that I shipped these two if it wasn't for you.

“Hey, Dip. Are you coming in?” Mabel snicked as she clung to the side of the pool, her face peeking out over the top.

“Are you sure we should be doing this, Mabel?” Dipper asked. It wasn't like they had never broken into the Gravity Falls pool before. It was something they'd done plenty of times since that first summer. But breaking into the pool to skinny dip at night with his twin was something different entirely.

“You aren't chickening out on me, are you?”

“No, of course not.” Dipper rubbed his arm. “I'm just kind of nervous. What if we get caught?”

“Bawk, bawk, bawk!” Mabel said, flapping her arms in the water.

“Shhh! Stop it!” Dipper said, glancing around. There was nothing there but the pool, the glow of the overhead lights gently illuminating the water. But he couldn't help but be nervous.

“Bawk, baaaaaaawk!”

“Okay, fine!” Keeping his gaze locked with Mabel's, he unbuttoned his red flannel and pulled down his pants and underwear before stepping out of them. “I'm doing it. Will you stop now?”

Mabel gave him a satisfied grin and put her fingers to her mouth, wolf whistling at him. 

Dipper went completely red. “Could you not do that either.”

“Whatever you say, bro bro~” Mabel practically purred. She pulled herself away from the edge and swam backwards, her breasts just barely poking above the water as she moved to float on her back. Dipper couldn't help but stare. He knew she was doing this specifically to tease him. It was always this way with Mabel. Though the two of them were more than just brother and sister now, she still acted like a goof. Except now she used it for more then just ruffling his feathers.

“Come on in, Dip. The water feels nice,” she said, closing her eyes and floating on her back.

Dipper took a step back before running towards the pool and jumping over the edge. The water enveloped his body, a slight shock running through his skin at the cold. He surfaced gasping for air but before he could really do a thing, Mabel tackled him in the water, laughing as she tried to climb up onto him. 

“I'm queen of the Dip!” she shouted, her hands on his shoulders and her feet clawing for support on his back.

“Mabel, you're clawing my back” Dipper said and he reached back and grabbed her by the legs. Mabel squealed and let go of him, falling back into the pool with a splash. 

“Help!” she called out. “This handsome stranger is touching my legs!”

“You were the one climbing on my back!” Dipper said, laughing as he pulled her around the pool.

“You know you liked it.” She struggled playfully against him and Dipper held on tighter. Dipper about faced and pulled her onto his shoulders, laughing as he gazed up at her.

“You look pretty good with your head between my legs,” Mabel purred.

“Well, you look good at any angle,” Dipper said, a blush creeping onto his face

Mabel laughed and pulled free of him, swimming around him and splashing his face with water. “You're so easy to fluster,” she said, giving him a triumphant grin.

“That's your fault,” Dipper said, sinking into the water a little.

Mabel's grin went from triumphant to something else entirely. Her eyes lidded, she swam up to him and wrapped her arms around his shoulder, pulling him against her. Dipper became entirely too aware of her state of undress as he felt her body pressing up against his. “In what way is it my fault?” she asked, leaning back so that she was now supporting his weight.

“Y-you know why,” Dipper stammered.

“I know you know. But I want to hear you say it~” she teased, leaning in so that her forehead was touching his.

Dipper looked her square in the eyes. “Because you look really good with no clothes on.” With that, he closed the distance between them. Her lips responded to his touch, coming to life against his. As his lips danced with hers, he found himself pressing her back against the edge of the pool. A soft noise escaped from the back of her throat and Dipper felt his heart do a little flip. A few months ago, he never would have thought a sound like that, coming from his twin, would be a turn on. But it was. It lit a fire inside his chest, the flames flickering and burning as he thought about how exposed the two of them were. He leaned closer, trying to press his body to hers, but Mabel pushed him back. 

Confused, Dipper pulled away from her, tilting his head and giving her a questioning look. But Mabel just smirked and pulled herself over the edge of the pool. The details of her body were laid bare for his eyes; her cute and perky breasts, her long legs and beautiful neck, the small bush between her thighs that hid the little bumps of skin he so desired to touch. She was so beautiful and he must have been staring a little longer then he meant to for Mabel giggled. “You know, you're not going to be getting any if you stay in the pool.”

This sent Dipper scrambling out after her. He'd been aroused enough in the pool but without the cold water all around him, his body was free to react to his sisters state of undress. And he could barely contain himself as he wrapped his arms around her waist and pulled her into another kiss.

Again, Mabel gave a light groan, her hands wrapping around his neck for support. “Diiiiip...” she managed to get out as their lips parted, his name drawn out and breathy. The way she looked to him sent a new shiver down his spine and what she wanted was confirmed as he felt his slip a hand down between him and trace her finger around the base of his growing erection. Dipper let out a gasp as the contact and she giggled before pulling away. “We should probably find someplace more private, don'tchya think?”

She took his hand in hers and gave it a tug, pulling him into the nearest changing room. It was darker inside then it was outside. But Dipper didn't need to see her. All he needed to be able to do was to feel her.

In the pitch black, he felt her take his hand again, this time guiding it up to her breasts. “Dipper...” she murmured again, pressing against him. “Please...I want you to make me feel good...”

“Mabel,” Dipper said, his breath catching in his throat. He knew where this was going and though he had never been particularly good at leading the situation, her words were indication enough that she wanted him to do so. He began to rub his hand up and down the mound, loving the way her breath hitched in her throat as he ran his thumb over one of her nipples. Wanting to hear more, he gave her a gentle push back against the wall and leaned in. Mabel gave a surprised gasp and then a soft moan as he grabbed her by the chin and captured her lips in another kiss. His hand worked one breast, then the other, feeling slightly dizzy with the giddy desire that was building inside him.

“Dipperrrr,” she moaned against his lips. He moved from her mouth to her face and then gradually down to her jawbone, peppering her with kisses. She whined and grabbed onto his arm for support, squeezing it hard. “Why are you always so slowww?” She took hold of his other hand and guided it to the space between her legs, indicating that she needed more. 

Another moan escaped her lips as Dipper gave her what she wanted, rubbing his fingers down the space between her folds. The grip on his arm tightened even harder. He rubbed and played with her, her whimpers and the way she arched into his hand telling him what she wanted and what she didn't. And after just a few minutes of this, she was panting into his ear, her hips grinding forward in blind lust. “Dipper,” whimpered again. “I...I need more then just this.” The words made Dipper incredibly aware of just how hard he was. She leaned in and gave him a kiss on the lips before she pushed his hand away.

At first Dipper was confused until he felt her pulling him down to the floor. In the adjusted darkness, he could just barely make out her form. Yet as she tugged him down on top of her, it became abundantly apparent that she was on her hands and knees. Dipper felt a blush creeping onto his face. He wished he could see her like this, kneeling on the floor below him. Still, he knew exactly what he wanted to do to her.

She let out a squeak as he leaned over her, pulling her back against him, his cock coming to rest between her thighs. One hand he used for support while the other wrapped around her chest, grabbing at one of her breasts. There was another squeak but it quickly turned into a moan as he began to rub himself between her thighs. “Shit...Dip...” she whimpered, her body quavering little under his weight. And as Dipper felt her thighs tighten a little around his cock, he couldn't stop the lewd moan that left his own mouth.

“Dipper...I want you... inside me,” Mabel said in a low, breathy voice. 

Her soft pleading was enough to move him forward. He began to probe upward, drawing out several moans as his head teased her, until finally he felt found her entrance. Dipper let out a shuddered gasp as he felt his cock slide up inside her. But it was nothing compared to the pleasured cry that Mabel gave.

“Oh god,” she whimpered and he felt her body shift under him just a little as she adjusted to the new weight. “It feels so big...”

A wave of heat washed over him at her words. He wasn't really that big. But he loved when Mabel said he was. He pulled back slowly before pressing himself back into her, drawing another heated moan from her. She felt so good around him. Dipper couldn't hide the heat in his own voice, his breathing ragged as he began to fuck her at a steady pace. 

Each thrust brought a new noise from her, a new “Oh god,” or “Shit”, but it wasn't long before she went from using words to simply crying out. He'd long since stopped paying attention to how loud they were being She adjusted her position every once in a while, trying to make it so he'd go deeper inside her. It wasn't long before he was slamming into her, his fingernails digging into her breasts as he let out his own string of audible noises. 

He loved being on top of her like this and she seemed to love it to. She jerked and twitched under him, her body covered in sweat. 

“D-dip...oh god...this feels so good.”

She seemed to have found her voice again and Dipper responded by giving her a particularly hard thrust. It must have hit a sweet spot for she cried out and tried to move her hips back against his. “D-do that again,” she begged and Dipper complied, letting out his own, drawn out moan. She was making him feel so good. He didn't think he could last much longer.

Luckily, she seemed to be on the same page for not moments after this thought, she let out a soft whisper; “I'm really close.” Knowing that she was edging towards her peak, he reached down and slid his finger between her legs, his hand finding her clit and rubbing it. She practically screamed under his attention and he knew she'd climaxed when he felt her tensing all around him. Dipper gave a few last desperate thrusts before he completely lost it.

Dipper pressed his forehead against her back as he rode out the high of his peak. He could feel her body trembling. “M-Mabel...fuck...” he whimpered. Her insides felt so hot and sticky and he gave a few last thrusts into her before he collapsed against her back, panting hard.

Mabel was strong but at the moment, her arms were jelly and when her brother put his entire weight on her, they quickly gave out. The two of them collapsed into a heap on the floor and Mabel simply remained there, a thin string of drool hanging out of her mouth.

“Wow...” Dipper said after recovering his breath a little. They'd never done anything else quite like that before. But it had been really hot. He rolled off his sister, realizing that he'd been squishing her, before pulling her against him, spooning with her on the changing room floor.

Mabel laughed at his words, her own breath slowly returning to normal. “Yeah...” she said in agreement. “That was...wow.”


End file.
